1. Field of the Invention
The present invention relates to an iron core assembly which generally forms a major or essential part of an electric motor, a transformer and the like, and it also relates to a method of producing such an iron core assembly.
2. Description of the Related Art
For example, an iron core assembly of the type mentioned above has been used in a conventional electric motor, as disclosed in Japanese unexamined patent publication (laid-open) No. 9-191588. As shown in FIGS. 58 and 59, such a kind of conventional iron core assembly comprises a predetermined number of core members 1 stacked or laminated one over another, each core member 1 being formed of a plurality of core segments 1a which are connected together by way of a plurality of thin portions 1b. In order to improve winding property or efficiency, the stacked core members 1 in their states as shown in FIG. 59 are wound with wires 2 by means of a winding machine (not shown), and the respective thin portions 1b thereof are then bent properly to form an annular or ring-shaped core assembly as shown in FIG. 58.
Since a conventional iron core assembly is constructed in the above-described manner, when a ring-shaped iron core assembly is formed, every two adjacent core segments 1 a facing each other through a thin portion 1b, and end faces of each edge portion of core segments 1a located on opposite ends of each core member 1, will undesirably produce some rough surface portions and some working size errors during a press punching process. As a result, every two adjacent core segments 1a will have to be brought together with an undesirable clearance of several micrometers (xcexcm) to ten-odd micrometers (xcexcm) formed therebetween. Due to the existence of such kind of clearances, a magnetic resistance will undesirably be increased, resulting in a problem that the magnetic performance of the iron core assembly is deteriorated.
Further, since each of the core members 1 forming an iron core assembly is usually provided on the surface thereof with a skin layer. Such a kind of skin layer is useful in hampering the passing of magnetic flux therethrough so as to inhibit a possible eddy current loss. For this reason, if there is no such kind of skin layer existing on the end faces of punched portions, an undesired eddy current will occur over the entire area of each end face of each core segment 1a in the laminating direction. Because of the occurrence of the eddy current, an undesired iron loss will happen, thus undesirably affecting a desired magnetic performance.
Moreover, on each of the above end faces, since a holding force intended to act against an external force in parallel with the end faces is relatively weak, the iron core assembly as a whole has only low rigidity. In particular, if an electric motor is a type in which a force caused by magnetism exerts on its iron core assembly, it will be difficult to ensure a required strength for the motor.
In addition, since each thin portion 1b is bent in a manner such that a circular configuration is formed as a whole, it is difficult to mechanically ensure high precision for an electric motor. Further, since bending treatment has to be performed for several times in order to form the desired circular configuration, some cracks will possibly occur in the thin portions 1b, resulting in some problems in which not only the mechanical strength is reduced, but also desired magnetic performance is deteriorated because the cracks will cause an increase in the magnetic resistance of a magnetic circuit.
In view of the above, the present invention is intended to obviate the above-discussed problems encountered with the conventional iron core assemblies, and has for its object to provide an improved iron core assembly of the character described and a method of manufacture thereof which are suitable for mass production and which are capable of inhibiting a possible increase in the magnetic resistance and a possible occurrence of an eddy current so as to obtain improved magnetic performance, thereby ensuring improved rigidity and increased mechanical precision for the iron core assembly.
Bearing the above object in mind, according to a first aspect of the present a plurality of layers (sometimes referred to herein as xe2x80x9ccore membersxe2x80x9d) of plate-shaped core segments having end portions, said core segments disposed in planar succession in each of the plurality of layers; and couplers (sometimes referred to herein as xe2x80x9ccoupling meansxe2x80x9d) coupling the end portions of the core segments of a first of the plurality of layers to the end portions of the adjacent core segments of a second of the plurality of layers; wherein said core segments of the first layer are laminated to the core segments of the second layer in such a manner that the end portions of the core segments of the first layer are offset from the end portions of adjacent core segments of the second layer which adjoin each other in a laminating direction that is perpendicular to the planar direction, and wherein said core segments are rotatable relative to each other through said couplers so as to form an enclosed or ring-like configuration.
With this arrangement, it is possible to provide an iron core assembly which is suitable for mas production and can be improved in its magnetic performance and mechanical strength.
In a preferred form of the first aspect of the invention, the coupling means couples together edge portions of those core segments which adjoin each other in the laminating direction of the first and second core members. Thus, it is possible to further improve the magnetic performance and mechanical strength of the iron core assembly.
In another preferred form of the first aspect of the invention, the coupling means comprises: first concave and convex portions respectively formed on a top surface and a back surface of each of the first core segments of the first core member at one end edge portion thereof; and second concave and convex portions respectively formed on a front surface and a bottom surface of each of the second core segments of the second core member at the other end edge portion thereof. The first concave and convex portions are engageable with the second concave and convex portions thereby to couple the edge portions of those core segments which adjoin each other in the laminating direction of the first and second core members.
With this arrangement, it is possible to improve not only the magnetic performance and mechanical strength, but also durability of the iron core assembly against bending operations upon assembling.
In a further preferred form of the first aspect of the invention, the first concave and convex portions are engageable with the second concave and convex portions through clearances. Accordingly, it becomes easy to rotate coupling portions of the iron core assembly.
In a yet further preferred form of the first aspect of the invention, the coupling means comprises: a first hole formed in one end edge portion of each first core segment of the first core member; a second hole in the other end edge portion of each second core segment of the second core member; and a pin member passing through the first and second holes in the laminated first and second core segments in the laminating direction of the first and second core members in such a manner as to allow relative rotation of the first and second core segments.
With this arrangement, it is possible not only to improve the magnetic performance and mechanical strength, but also further expedite rotation of the iron core assembly upon assemblage thereof, thus ensuring improved assembling precision.
In a still further preferred form of the first aspect of the invention, each first core segment of the first core member has one end face at least partially formed into a convex arc-shaped configuration and the other end face at least partially formed into a concave arc-shaped configuration, with the convex arc-shaped one end face of each first core segment being disposed in abutment with the other concave arc-shaped end face of a first core segment adjoining in a direction in which the first core segments are disposed in succession; each second core segment of the second core member has one end face at least partially formed into a concave arc-shaped configuration and the other end face at least partially formed into a convex arc-shaped configuration, with the concave arc-shaped one end face of each second core segment being disposed in abutment with the other convex arc-shaped end face of a second core segment adjoining in a direction in which the second core segments are disposed in succession; and a center of rotation of the coupling means which couples the edge portions of mutually adjacent core segments of the same core member with each other is disposed at a location which is substantially on a bisector for an angle formed by widthwise centerlines of mutually adjacent two core segments of the same core member and which is outwardly away from an intersection of the widthwise centerlines. With this arrangement, it is possible to expedite press-punching operation without deteriorating the magnetic performance of the iron core assembly.
In a further preferred form of the first aspect of the invention, a center of rotation of the coupling means which rotates each core segment is disposed at a location which is substantially on a bisector for an angle formed by widthwise centerlines of mutually adjacent two core segments of the same core member and which is outwardly away from an intersection of the widthwise centerlines. Thus, press-punching operation can be further improved without affecting the magnetic performance of the iron core assembly.
In a further preferred form of the first aspect of the invention, the coupling means couples adjacent edge portions of successively disposed adjacent core segments of the same first or second core member with each other. Accordingly, it is possible to further improve the magnetic performance and mechanical strength of the iron core assembly.
In a further preferred form of the first aspect of the invention, the coupling means comprises opposing end faces of mutually adjacent edge portions of successively disposed core segments of the first or second core members, the opposing end faces being formed into an articulated configuration. Thus, assembling precision can be further improved, in addition to enhancing the magnetic performance and mechanical strength.
In a further preferred form of the first aspect of the invention, the first core member and the second core member are laminated to form a laminated core unit which has opposite ends formed into complementary stepped configurations in which edge portions of mutually opposed core segments at the opposite ends of the laminated are superposed each other in a stepwise fashion in the laminating direction. Thus, it is possible to improve efficiency in assembling operation.
In a further preferred form of the first aspect of the invention, the first core member and the second core member are laminated to form a laminated core unit which is formed at opposite ends thereof with a concave portion and a convex portion which are formed on core segments mutually adjoining each other in the laminating direction and which are detachably engageable with each other. Accordingly, assembling efficiency can be further improved.
In a further preferred form of the first aspect of the invention, rotation restricting means is provided on opposing end faces of adjacent edge portions of successively disposed core segments of the first or second core member for restricting rotation of the coupling means when the laminated first and second core members are formed into the enclosed or ring-like configuration. Accordingly, it becomes possible to position the first or second core member in an easy manner, thus further improving the assembling efficiency.
In a further preferred form of the first aspect of the invention, reverse-rotation restricting means is provided on opposing end faces of adjacent edge portions of successively disposed core segments of the first or second core member for restricting reverse rotation of the coupling means. Accordingly, wire winding operation can be expedited, thereby improving assembling efficiency.
According to a second aspect of the present invention, there is provided an iron core assembly comprising: a first plurality of layers (sometimes referred to herein as xe2x80x9ccore membersxe2x80x9d) of core segment blocks having end portions, said core segment blocks disposed in planar succession in each of the plurality of layers, said core segment blocks each having a plurality of plate-shaped core segments laminated one over another; couplers (sometimes referred to herein as xe2x80x9ccoupling meansxe2x80x9d) for coupling the end portions of the core segment blocks of a first of the plurality of layers to the end portions of the core segment blocks of a second of the plurality of layers; wherein said core segment blocks of the first layer are laminated to the core segment blocks of the second layer in such a manner that the end portions of the core segment blocks of the first layer are offset from the end portions of adjacent core segment blocks of the second layer which adjoin each other in a laminating direction that is perpendicular to the planar direction, and wherein said core segment blocks are rotatable relative to each other through said couplers so as to form an enclosed or ring-like configuration.
With this arrangement, the magnetic performance and mechanical strength of the iron core assembly can be improved, and the number of component parts of the core assembly can be reduced, thus enhancing productivity. Beside, when the core segment blocks are to be rotated tooth by tooth, such rotation becomes easy due to reduced friction.
In a preferred form of the second aspect of the invention, the coupling means couples together edge portions of those core segment blocks which adjoin each other in the laminating direction of the first and second core members. Thus, the magnetic performance and mechanical strength can be further improved.
In another preferred form of the second aspect of the invention, the coupling means comprises: a first hole formed in one end edge portion of each first core segment block of the first core member; a second hole in the other end edge portion of each second core segment block of the second core member; and a pin member passing through the first and second holes in the laminated first and second core segment blocks in the laminating direction of the first and second core members in such a manner as to allow relative rotation of the first and second core segment blocks. Accordingly, beside the fact that the magnetic performance and mechanical strength can be improved, it becomes further easy to effect rotation of the core segment blocks, thereby enhancing assembling precision.
In a further preferred form of the second aspect of the invention, edge portions of successively disposed core segment blocks of the first or second core member have opposing end faces one of which is formed into a convex arc-shaped configuration, and the other of which is formed into a concave arc-shaped configuration, a convex arc-shaped end face of one of the mutually adjacent core segment blocks being disposed in abutment with a concave arc-shaped end face of the other of the mutually adjacent core segment blocks which is adjacent the one core segment block of the same core member. Thus, the magnetic performance can be further improved.
According to a third aspect of the present invention, there is provided an iron core assembly comprising: a first laminated core unit; and a second laminated core unit. The first laminated core unit comprises: a first core member having a plurality of plate-shaped first core segments disposed in succession; a second core member having a plurality of plate-shaped second core segments disposed in succession; and first coupling means for coupling edge portions of adjacent core segments of the first and second core members. The first and second core members are alternately laminated one over another in such a manner that first inter-segment positions each defined between adjacent two first core segments of the first core member are offset from second inter-segment positions each defined between adjacent two second core segments of the second core member in a longitudinal direction of the first and second core members, with those edge portions of the respective first and second core segments which adjoin each other in a laminating direction in which the first and second core members are laminated being overlapped each other. The second laminated core unit comprises: a third core member having a plurality of plate-shaped third core segments disposed in succession; a fourth core member having a plurality of plate-shaped fourth core segments disposed in succession; and second coupling means for coupling edge portions of adjacent core segments of the third and fourth core members. The third and fourth core members are alternately laminated one over another in such a manner that third inter-segment positions each defined between adjacent two third core segments of the third core member are offset from fourth inter-segment positions each defined between adjacent two fourth core segments of the fourth core member in a longitudinal direction of the third and fourth core members, with those edge portions of the respective third and fourth core segments which adjoin each other in a laminating direction in which the third and fourth core members are laminated being overlapped each other. The core segments of the first and second core units are rotated relative to each other through the first and second coupling means so as to form an enclosed or ring-like configuration.
With the above arrangement, the entire laminated core can be divided into a plurality of core units each having such a size as suitable for assembling operation, thus improving assembling efficiency.
According to a fourth second aspect of the present invention, there is provided an iron core assembly comprising: a first laminated core unit which comprises: a first core member having a plurality of plate-shaped first core segments disposed in succession; a second core member having a plurality of plate-shaped second core segments disposed in succession; and coupling means for coupling edge portions of adjacent core segments of the first and second core members. The first and second core members are alternately laminated one over another in such a manner that first inter-segment positions each defined between adjacent two first core segments of the first core member are offset from second inter-segment positions each defined between adjacent two second core segments of the second core member in a longitudinal direction of the first and second core members, with those edge portions of the respective first and second core segments which adjoin each other in a laminating direction in which the first and second core members are laminated being overlapped each other. A second laminated core unit has a plurality of plate-shaped core segments laminated one over another. The core segments of the first laminated core unit are rotated relative to each other through the coupling means thereby to combine the first and second core units so as to form an enclosed or ring-like configuration. Thus, just like the above, the entire laminated core can be divided into a plurality of core units each having a size suitable for assembling operation, and hence assembling efficiency can be improved.
According to a fifth aspect of the present invention, there is provided a method for producing an iron core assembly, the method comprising the steps of: disposing a plurality of plate-shaped first core segments in succession to form first core members; disposing a plurality of plate-shaped second core segments in succession to form second core members; alternately laminating first and second core members one over another in such a manner that first inter-segment positions each defined between adjacent two first core segments of each first core member are offset from second inter-segment positions each defined between adjacent two second core segments of each second core member in a longitudinal direction of the first and second core members, with those edge portions of the respective first and second core segments which adjoin each other in a laminating direction in which the first and second core members are laminated being overlapped each other; coupling edge portions of adjacent core segments of the first and second core members through coupling means; and rotating the core segments of the first and second core members relative to each other through the coupling means so as to form an enclosed or ring-like configuration. Thus, an improved iron core assembly can be obtained which has improved magnetic performance and mechanical strength.
According to a sixth aspect of the present invention, there is provided a method for producing an iron core assembly, the method comprising the steps of: laminating a plurality of plate-shaped first core segments one over another to form first core segment blocks; laminating a plurality of plate-shaped second core segments one over another to form second core segment blocks; successively disposing the first core segment blocks in a line to provide first core members; successively disposing the second core segment blocks in a line to provide second core members; alternately laminating first and second core members one over another in a direction in which the first and second core segments are laminated, in such a manner that first inter-block positions each defined between adjacent two first core segment blocks of each first core member are offset from second inter-block positions each defined between adjacent two second core segment blocks of each second core member in a longitudinal direction of the first and second core members, with those edge portions of the respective first and second core segments which adjoin each other in a direction in which the first and second core members are laminated being overlapped each other; coupling edge portions of respective adjacent core segment blocks of the first and second core members through coupling means; and rotating the core segment blocks of the first and second core members relative to each other through the coupling means so as to form an enclosed or ring-like configuration.
With this arrangement, as described above, the magnetic performance and mechanical strength of the iron core assembly can be improved, and the number of component parts of the core assembly can be reduced for improved productivity. Moreover, when the core segment blocks are to be rotated tooth by tooth, it becomes easy to effect such rotation due to reduced friction.
According to another aspect of the present invention, an iron core assembly includes a plurality of layers of independent plate-shaped core segments having end portions, said core segments disposed in planar succession in each of the plurality of layers; and couplers coupling the end portions of the core segments of a first of the plurality of layers to adjacent ones of the end portions of the core segments of the first layer; wherein said core segments of the first layer are laminated to the core segments of the second layer in such a manner that the end portions of the core segments of the first layer are offset in a planar direction from the end portions of adjacent core segments of the second layer which adjoin each other in a laminating direction that is perpendicular to the planar direction, and wherein said core segments of said first and second layers are rotatable relative to each other through said couplers so as to form an enclosed or ring-like configuration.
According to yet another aspect of the present invention, an iron core assembly includes a plurality of layers of independent plate-shaped core segments, each of the core segments having first and second end portions, said core segments disposed in planar succession in each of the plurality of layers; the core segments of a first of the plurality of layers are laminated to the core segments of a second of the plurality of layers in such a manner that the end portions of the core segments of the first layer are offset from the end portions of the core segments of the second layer in a longitudinal planar direction of said layers of core segments, and so that each of the first end portions of the core segments of the first layer overlaps a first end portion of one of the core segments of the second layer and each of the second end portion of the core segments of the first layer overlaps an end portion of another one of the core segments of the second layer; and couplers at the end portions of said core segments are rotatably engaged to each other through said end portions so as to form an enclosed or ring-like configuration.
The above and other objects, features and advantages of the present invention will more readily apparent from the following detailed description of preferred embodiments of the invention when taken in conjunction with the accompanying drawings.